Coated light-turning feature with auxiliary structure

ABSTRACT

This disclosure provides systems, methods and apparatus for a front illumination device with metalized light-turning features. In one aspect, an illumination device includes a light guide having light-turning features that include recesses formed on the light guide and that extend down into the light guide. The recesses may be coated with a material where the material also forms an auxiliary structure outside of the recesses on the light guide. The auxiliary structure may be conductive and may form, for example, an electrode.

CROSS-REFERENCE TO RELATED APPLICATIONS

This disclosure claims priority to U.S. Provisional Patent ApplicationNo. 61/290,868, filed Dec. 29, 2009, entitled “FRONT ILLUMINATION DEVICEWITH TOUCH SENSOR FUNCTIONALITY.” The disclosure of the priorapplication is considered part of, and is incorporated by reference in,this disclosure.

TECHNICAL FIELD

This disclosure relates generally to electromechanical systems anddisplay devices for actively displaying images. More specifically, someimplementations relate to an illumination device for display devices.Some implementations relate to touch-screen sensor devices andelectrodes. In some implementations, an illumination device and atouch-screen sensor device are integrated into a single illuminationdevice with integrated touch sensor capability.

DESCRIPTION OF THE RELATED TECHNOLOGY

Electromechanical systems include devices having electrical andmechanical elements, actuators, transducers, sensors, optical components(e.g., mirrors) and electronics. Electromechanical systems can bemanufactured at a variety of scales including, but not limited to,microscales and nanoscales. For example, microelectromechanical systems(MEMS) devices can include structures having sizes ranging from about amicron to hundreds of microns or more. Nanoelectromechanical systems(NEMS) devices can include structures having sizes smaller than a micronincluding, for example, sizes smaller than several hundred nanometers.Electromechanical elements may be created using deposition, etching,lithography, and/or other micromachining processes that etch away partsof substrates and/or deposited material layers, or that add layers toform electrical and electromechanical devices.

One type of electromechanical systems device is called aninterferometric modulator (IMOD). As used herein, the terminterferometric modulator or interferometric light modulator refers to adevice that selectively absorbs and/or reflects light using theprinciples of optical interference. In some implementations, aninterferometric modulator may include a pair of conductive plates, oneor both of which may be transparent and/or reflective, wholly or inpart, and capable of relative motion upon application of an appropriateelectrical signal. In an implementation, one plate may include astationary layer deposited on a substrate and the other plate mayinclude a metallic membrane separated from the stationary layer by anair gap. The position of one plate in relation to another can change theoptical interference of light incident on the interferometric modulator.Interferometric modulator devices have a wide range of applications, andare anticipated to be used in improving existing products and creatingnew products, especially those with display capabilities.

Reflected ambient light is used to form images in some display devices,such as those using pixels formed by interferometric modulators. Theperceived brightness of these displays depends upon the amount of lightthat is reflected towards a viewer. In low ambient light conditions,light from an artificial light source is used to illuminate thereflective pixels, which then reflect the light towards a viewer togenerate an image. To meet market demands and design criteria, newillumination devices are continually being developed to meet the needsof display devices, including reflective and transmissive displays.

SUMMARY

The systems, methods and devices of the disclosure each have severalinnovative aspects, no single one of which is solely responsible for thedesirable attributes disclosed herein.

One innovative aspect of the subject matter described in this disclosurecan be implemented in an illumination device that includes a light guidecomprising light-turning features. The light-turning features includerecesses formed on the light guide and extending down into the lightguide with a material coating at least some of the recesses. Theillumination device includes an auxiliary structure formed outside ofthe recesses and on the light guide, the auxiliary structure at leastpartially formed of the material coating at least some of the recesses.In certain implementations, the light guide may have a top surface, andthe light-turning features may be formed on the top surface of the lightguide. In certain implementations, the auxiliary structure may be formedon the top surface of the light guide. In certain implementations, thematerial may include a metal.

Another innovative aspect of the subject matter described in thisdisclosure can be implemented in a method of manufacturing an integratedillumination device that includes depositing a material on a light guidethat includes light-turning features. The light-turning features includerecesses formed on the light guide and extending down into the lightguide. The method also includes etching the deposited material to forman auxiliary structure and simultaneously leaving some of the materialin the recesses formed on the light guide. In certain implementations,the light guide has a top surface, the light-turning features are formedon the top surface of the light guide, and the material is deposited onthe top surface of the light guide. In certain implementations, theauxiliary structure is formed on the top surface of the light guide. Incertain implementations, the material includes a metal.

Another innovative aspect of the subject matter described in thisdisclosure can be implemented in an illumination device that includes aguiding means for guiding light that includes turning means for turninglight out of the guiding means, a coating means for coating at leastsome of the turning means to render the turning means reflective, and aconductive means for conducting electricity, where the conductive meansis formed outside of the turning means and formed of the same materialas the coating means. In certain implementations, the guiding meansincludes a light guide, the turning means includes a light-turningfacet, the coating means includes a reflective material, or theconductive means includes a conductive material.

Details of one or more implementations of the subject matter describedin this specification are set forth in the accompanying drawings and thedescription below. Other features, aspects, and advantages will becomeapparent from the description, the drawings, and the claims. Note thatthe relative dimensions of the following figures may not be drawn toscale.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of an isometric view depicting two adjacentpixels in a series of pixels of an interferometric modulator (IMOD)display device.

FIG. 2 shows an example of a system block diagram illustrating anelectronic device incorporating a 3×3 interferometric modulator display.

FIG. 3A shows an example of a diagram illustrating movable reflectivelayer position versus applied voltage for the interferometric modulatorof FIG. 1.

FIG. 3B shows an example of a table illustrating various states of aninterferometric modulator when various common and segment voltages areapplied.

FIG. 4A shows an example of a diagram illustrating a frame of displaydata in the 3×3 interferometric modulator display of FIG. 2.

FIG. 4B shows an example of a timing diagram for common and segmentsignals that may be used to write the frame of display data illustratedin FIG. 4A.

FIG. 5A shows an example of a partial cross-section of theinterferometric modulator display of FIG. 1.

FIGS. 5B-5E show examples of cross-sections of varying implementationsof interferometric modulators.

FIG. 6 shows an example of a flow diagram illustrating a manufacturingprocess for an interferometric modulator.

FIGS. 7A-7E show examples of cross-sectional schematic illustrations ofvarious stages in a method of making an interferometric modulator.

FIG. 8A is an example of an illustration of a display being illuminatedby an illumination device.

FIG. 8B is an example of an illustration of a display with anillumination device and a touch sensor.

FIG. 8C is an example of an illustration of an implementation of adisplay with an integrated illumination device with touch sensor.

FIG. 9A is an example of an illustration of an implementation of a lightguide.

FIG. 9B is an example of an illustration of an implementation of a lightguide with metalized light-turning features.

FIG. 9C is an example of a cross-sectional view of an implementation ofa light guide with metalized light-turning features with integratedtouch sensor.

FIG. 9D is an example of an illustration of a cross-sectional view of animplementation with metalized-light-turning features and touch-sensingelectrodes.

FIG. 10A is an example of an illustration of an implementation of atouch sensor.

FIGS. 10B-10C are examples of illustrations of implementations ofillumination devices with an integrated touch sensor.

FIG. 11A is an example of an illustration of an implementation of alight guide with metalized light-turning features integrated with atouch sensor.

FIG. 11B is an example of an illustration of an implementation of alight guide with layers of material deposited on the surfaces oflight-turning features and structures composed of those layers formedoutside of the light-turning features.

FIGS. 12A-12B are examples of illustrations of implementations of lightguides with metalized light-turning features with integrated touchsensor.

FIGS. 13A and 13B show examples of system block diagrams illustrating adisplay device that includes a plurality of interferometric modulators.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

The following detailed description is directed to certainimplementations for the purposes of describing the innovative aspects.However, the teachings herein can be applied in a multitude of differentways. The described implementations may be implemented in any devicethat is configured to display an image, whether in motion (e.g., video)or stationary (e.g., still image), and whether textual, graphical orpictorial. More particularly, it is contemplated that theimplementations may be implemented in or associated with a variety ofelectronic devices such as, but not limited to, mobile telephones,multimedia Internet enabled cellular telephones, mobile televisionreceivers, wireless devices, smartphones, bluetooth devices, personaldata assistants (PDAs), wireless electronic mail receivers, hand-held orportable computers, netbooks, notebooks, smartbooks, printers, copiers,scanners, facsimile devices, GPS receivers/navigators, cameras, MP3players, camcorders, game consoles, wrist watches, clocks, calculators,television monitors, flat panel displays, electronic reading devices(e.g., e-readers), computer monitors, auto displays (e.g., odometerdisplay, etc.), cockpit controls and/or displays, camera view displays(e.g., display of a rear view camera in a vehicle), electronicphotographs, electronic billboards or signs, projectors, architecturalstructures, microwaves, refrigerators, stereo systems, cassetterecorders or players, DVD players, CD players, VCRs, radios, portablememory chips, washers, dryers, washer/dryers, packaging (e.g., MEMS andnon-MEMS), aesthetic structures (e.g., display of images on a piece ofjewelry) and a variety of electromechanical systems devices. Theteachings herein also can be used in non-display applications such as,but not limited to, electronic switching devices, radio frequencyfilters, sensors, accelerometers, gyroscopes, motion-sensing devices,magnetometers, inertial components for consumer electronics, parts ofconsumer electronics products, varactors, liquid crystal devices,electrophoretic devices, drive schemes, manufacturing processes,electronic test equipment. Thus, the teachings are not intended to belimited to the implementations depicted solely in the Figures, butinstead have wide applicability as will be readily apparent to onehaving ordinary skill in the art.

Various implementations disclosed herein relate to an illuminationdevice. In some implementations, the illumination devices includes alight guide overlaid by one or more layers of material that coatlight-turning features and by auxiliary structures that are formed fromone or more of those layers and are outside of the light-turningfeatures. The light-turning features may be defined by recesses in thelight guide. The layers of material line the recesses. Outside of therecesses, the auxiliary structures may be formed on the light guide fromone or more of those layers of material. Where the one or more layers ofmaterial are conductive, these auxiliary structures may be conductivefeatures for forming passive or active electronic devices. For example,these other structures may be conductive electrodes, such as for atouch-sensing panel.

Particular implementations of the subject matter described in thisdisclosure can be implemented to realize one or more of the followingpotential advantages. For example, some implementations of theillumination device described herein include metalized light-turningfeatures that may improve the functionality of the light-turningfeatures. At the same time, the illumination device may also haveauxiliary structures such as active or passive electrical devices orstructures. The auxiliary structures and the metalized light-turningfeatures may advantageously be manufactured using the same depositionand lithographic process. In this way, an integrated illumination devicemay be manufactured in fewer steps than it would take to manufacture theauxiliary structures and the metalized light-turning featuresseparately. In addition, integrating electric structures with thelight-turning features allows the formation of thinner devices thanwould be available if different layers of material were used forlight-turning features and the auxiliary structures.

One example of a suitable MEMS device, to which the describedimplementations may apply, is a reflective display device. Reflectivedisplay devices can incorporate interferometric modulators (IMODs) toselectively absorb and/or reflect light incident thereon usingprinciples of optical interference. IMODs can include an absorber, areflector that is movable with respect to the absorber, and an opticalresonant cavity defined between the absorber and the reflector. Thereflector can be moved to two or more different positions, which canchange the size of the optical resonant cavity and thereby affect thereflectance of the interferometric modulator. The reflectance spectrumsof IMODs can create fairly broad spectral bands which can be shiftedacross the visible wavelengths to generate different colors. Theposition of the spectral band can be adjusted by changing the thicknessof the optical resonant cavity, i.e., by changing the position of thereflector.

FIG. 1 shows an example of an isometric view depicting two adjacentpixels in a series of pixels of an interferometric modulator (IMOD)display device. The IMOD display device includes one or moreinterferometric MEMS display elements. In these devices, the pixels ofthe MEMS display elements can be in either a bright or dark state. Inthe bright (“relaxed,” “open” or “on”) state, the display elementreflects a large portion of incident visible light, e.g., to a user.Conversely, in the dark (“actuated,” “closed” or “off”) state, thedisplay element reflects little incident visible light. In someimplementations, the light reflectance properties of the on and offstates may be reversed. MEMS pixels can be configured to reflectpredominantly at particular wavelengths allowing for a color display inaddition to black and white.

The IMOD display device can include a row/column array of IMODs. EachIMOD can include a pair of reflective layers, i.e., a movable reflectivelayer and a fixed partially reflective layer, positioned at a variableand controllable distance from each other to form an air gap (alsoreferred to as an optical gap or cavity). The movable reflective layermay be moved between at least two positions. In a first position, i.e.,a relaxed position, the movable reflective layer can be positioned at arelatively large distance from the fixed partially reflective layer. Ina second position, i.e., an actuated position, the movable reflectivelayer can be positioned more closely to the partially reflective layer.Incident light that reflects from the two layers can interfereconstructively or destructively depending on the position of the movablereflective layer, producing either an overall reflective ornon-reflective state for each pixel. In some implementations, the IMODmay be in a reflective state when unactuated, reflecting light withinthe visible spectrum, and may be in a dark state when unactuated,reflecting light outside of the visible range (e.g., infrared light). Insome other implementations, however, an IMOD may be in a dark state whenunactuated, and in a reflective state when actuated. In someimplementations, the introduction of an applied voltage can drive thepixels to change states. In some other implementations, an appliedcharge can drive the pixels to change states.

The depicted portion of the pixel array in FIG. 1 includes two adjacentinterferometric modulators 12. In the IMOD 12 on the left (asillustrated), a movable reflective layer 14 is illustrated in a relaxedposition at a predetermined distance from an optical stack 16, whichincludes a partially reflective layer. The voltage V₀ applied across theIMOD 12 on the left is insufficient to cause actuation of the movablereflective layer 14. In the IMOD 12 on the right, the movable reflectivelayer 14 is illustrated in an actuated position near or adjacent theoptical stack 16. The voltage V_(bias) applied across the IMOD 12 on theright is sufficient to maintain the movable reflective layer 14 in theactuated position.

In FIG. 1, the reflective properties of pixels 12 are generallyillustrated with arrows 13 indicating light incident upon the pixels 12,and light 15 reflecting from the pixel 12 on the left. Although notillustrated in detail, it will be understood by one having ordinaryskill in the art that most of the light 13 incident upon the pixels 12will be transmitted through the transparent substrate 20, toward theoptical stack 16. A portion of the light incident upon the optical stack16 will be transmitted through the partially reflective layer of theoptical stack 16, and a portion will be reflected back through thetransparent substrate 20. The portion of light 13 that is transmittedthrough the optical stack 16 will be reflected at the movable reflectivelayer 14, back toward (and through) the transparent substrate 20.Interference (constructive or destructive) between the light reflectedfrom the partially reflective layer of the optical stack 16 and thelight reflected from the movable reflective layer 14 will determine thewavelength(s) of light 15 reflected from the pixel 12.

The optical stack 16 can include a single layer or several layers. Thelayer(s) can include one or more of an electrode layer, a partiallyreflective and partially transmissive layer and a transparent dielectriclayer. In some implementations, the optical stack 16 is electricallyconductive, partially transparent and partially reflective, and may befabricated, for example, by depositing one or more of the above layersonto a transparent substrate 20. The electrode layer can be formed froma variety of materials, such as various metals, for example indium tinoxide (ITO). The partially reflective layer can be formed from a varietyof materials that are partially reflective, such as various metals,e.g., chromium (Cr), semiconductors, and dielectrics. The partiallyreflective layer can be formed of one or more layers of materials, andeach of the layers can be formed of a single material or a combinationof materials. In some implementations, the optical stack 16 can includea single semi-transparent thickness of metal or semiconductor whichserves as both an optical absorber and conductor, while different, moreconductive layers or portions (e.g., of the optical stack 16 or of otherstructures of the IMOD) can serve to bus signals between IMOD pixels.The optical stack 16 also can include one or more insulating ordielectric layers covering one or more conductive layers or aconductive/absorptive layer.

In some implementations, the layer(s) of the optical stack 16 can bepatterned into parallel strips, and may form row electrodes in a displaydevice as described further below. As will be understood by one havingskill in the art, the term “patterned” is used herein to refer tomasking as well as etching processes. In some implementations, a highlyconductive and reflective material, such as aluminum (Al), may be usedfor the movable reflective layer 14, and these strips may form columnelectrodes in a display device. The movable reflective layer 14 may beformed as a series of parallel strips of a deposited metal layer orlayers (orthogonal to the row electrodes of the optical stack 16) toform columns deposited on top of posts 18 and an intervening sacrificialmaterial deposited between the posts 18. When the sacrificial materialis etched away, a defined gap 19, or optical cavity, can be formedbetween the movable reflective layer 14 and the optical stack 16. Insome implementations, the spacing between posts 18 may be on the orderof 1-1000 um, while the gap 19 may be on the order of <10,000 Angstroms(Å).

In some implementations, each pixel of the IMOD, whether in the actuatedor relaxed state, is essentially a capacitor formed by the fixed andmoving reflective layers. When no voltage is applied, the movablereflective layer 14 a remains in a mechanically relaxed state, asillustrated by the pixel 12 on the left in FIG. 1, with the gap 19between the movable reflective layer 14 and optical stack 16. However,when a potential difference, e.g., voltage, is applied to at least oneof a selected row and column, the capacitor formed at the intersectionof the row and column electrodes at the corresponding pixel becomescharged, and electrostatic forces pull the electrodes together. If theapplied voltage exceeds a threshold, the movable reflective layer 14 candeform and move near or against the optical stack 16. A dielectric layer(not shown) within the optical stack 16 may prevent shorting and controlthe separation distance between the layers 14 and 16, as illustrated bythe actuated pixel 12 on the right in FIG. 1. The behavior is the sameregardless of the polarity of the applied potential difference. Though aseries of pixels in an array may be referred to in some instances as“rows” or “columns,” a person having ordinary skill in the art willreadily understand that referring to one direction as a “row” andanother as a “column” is arbitrary. Restated, in some orientations, therows can be considered columns, and the columns considered to be rows.Furthermore, the display elements may be evenly arranged in orthogonalrows and columns (an “array”), or arranged in non-linear configurations,for example, having certain positional offsets with respect to oneanother (a “mosaic”). The terms “array” and “mosaic” may refer to eitherconfiguration. Thus, although the display is referred to as including an“array” or “mosaic,” the elements themselves need not be arrangedorthogonally to one another, or disposed in an even distribution, in anyinstance, but may include arrangements having asymmetric shapes andunevenly distributed elements.

FIG. 2 shows an example of a system block diagram illustrating anelectronic device incorporating a 3×3 interferometric modulator display.The electronic device includes a processor 21 that may be configured toexecute one or more software modules. In addition to executing anoperating system, the processor 21 may be configured to execute one ormore software applications, including a web browser, a telephoneapplication, an email program, or any other software application.

The processor 21 can be configured to communicate with an array driver22. The array driver 22 can include a row driver circuit 24 and a columndriver circuit 26 that provide signals to, e.g., a display array orpanel 30. The cross section of the IMOD display device illustrated inFIG. 1 is shown by the lines 1-1 in FIG. 2. Although FIG. 2 illustratesa 3×3 array of IMODs for the sake of clarity, the display array 30 maycontain a very large number of IMODs, and may have a different number ofIMODs in rows than in columns, and vice versa.

FIG. 3A shows an example of a diagram illustrating movable reflectivelayer position versus applied voltage for the interferometric modulatorof FIG. 1. For MEMS interferometric modulators, the row/column (i.e.,common/segment) write procedure may take advantage of a hysteresisproperty of these devices as illustrated in FIG. 3A. An interferometricmodulator may require, for example, about a 10-volt potential differenceto cause the movable reflective layer, or mirror, to change from therelaxed state to the actuated state. When the voltage is reduced fromthat value, the movable reflective layer maintains its state as thevoltage drops back below, e.g., 10-volts, however, the movablereflective layer does not relax completely until the voltage drops below2-volts. Thus, a range of voltage, approximately 3 to 7-volts, as shownin FIG. 3A, exists where there is a window of applied voltage withinwhich the device is stable in either the relaxed or actuated state. Thisis referred to herein as the “hysteresis window” or “stability window.”For a display array 30 having the hysteresis characteristics of FIG. 3A,the row/column write procedure can be designed to address one or morerows at a time, such that during the addressing of a given row, pixelsin the addressed row that are to be actuated are exposed to a voltagedifference of about 10-volts, and pixels that are to be relaxed areexposed to a voltage difference of near zero volts. After addressing,the pixels are exposed to a steady state or bias voltage difference ofapproximately 5-volts such that they remain in the previous strobingstate. In this example, after being addressed, each pixel sees apotential difference within the “stability window” of about 3-7-volts.This hysteresis property feature enables the pixel design, e.g.,illustrated in FIG. 1, to remain stable in either an actuated or relaxedpre-existing state under the same applied voltage conditions. Since eachIMOD pixel, whether in the actuated or relaxed state, is essentially acapacitor formed by the fixed and moving reflective layers, this stablestate can be held at a steady voltage within the hysteresis windowwithout substantially consuming or losing power. Moreover, essentiallylittle or no current flows into the IMOD pixel if the applied voltagepotential remains substantially fixed.

In some implementations, a frame of an image may be created by applyingdata signals in the form of “segment” voltages along the set of columnelectrodes, in accordance with the desired change (if any) to the stateof the pixels in a given row. Each row of the array can be addressed inturn, such that the frame is written one row at a time. To write thedesired data to the pixels in a first row, segment voltagescorresponding to the desired state of the pixels in the first row can beapplied on the column electrodes, and a first row pulse in the form of aspecific “common” voltage or signal can be applied to the first rowelectrode. The set of segment voltages can then be changed to correspondto the desired change (if any) to the state of the pixels in the secondrow, and a second common voltage can be applied to the second rowelectrode. In some implementations, the pixels in the first row areunaffected by the change in the segment voltages applied along thecolumn electrodes, and remain in the state they were set to during thefirst common voltage row pulse. This process may be repeated for theentire series of rows, or alternatively, columns, in a sequentialfashion to produce the image frame. The frames can be refreshed and/orupdated with new image data by continually repeating this process atsome desired number of frames per second.

The combination of segment and common signals applied across each pixel(that is, the potential difference across each pixel) determines theresulting state of each pixel. FIG. 3B shows an example of a tableillustrating various states of an interferometric modulator when variouscommon and segment voltages are applied. As will be readily understoodby one having ordinary skill in the art, the “segment” voltages can beapplied to either the column electrodes or the row electrodes, and the“common” voltages can be applied to the other of the column electrodesor the row electrodes.

As illustrated in FIG. 3B (as well as in the timing diagram shown inFIG. 4B), when a release voltage VC_(REL) is applied along a commonline, all interferometric modulator elements along the common line willbe placed in a relaxed state, alternatively referred to as a released orunactuated state, regardless of the voltage applied along the segmentlines, i.e., high segment voltage VS_(H) and low segment voltage VS_(L).In particular, when the release voltage VC_(REL) is applied along acommon line, the potential voltage across the modulator (alternativelyreferred to as a pixel voltage) is within the relaxation window (seeFIG. 3A, also referred to as a release window) both when the highsegment voltage VS_(H) and the low segment voltage VS_(L) are appliedalong the corresponding segment line for that pixel.

When a hold voltage is applied on a common line, such as a high holdvoltage VC_(HOLD) _(—) _(H) or a low hold voltage VC_(HOLD) _(—) _(L),the state of the interferometric modulator will remain constant. Forexample, a relaxed IMOD will remain in a relaxed position, and anactuated IMOD will remain in an actuated position. The hold voltages canbe selected such that the pixel voltage will remain within a stabilitywindow both when the high segment voltage VS_(H) and the low segmentvoltage VS_(L) are applied along the corresponding segment line. Thus,the segment voltage swing, i.e., the difference between the high VS_(H)and low segment voltage VS_(L), is less than the width of either thepositive or the negative stability window.

When an addressing, or actuation, voltage is applied on a common line,such as a high addressing voltage VC_(ADD) _(—) _(H) or a low addressingvoltage VC_(ADD) _(—) _(L), data can be selectively written to themodulators along that line by application of segment voltages along therespective segment lines. The segment voltages may be selected such thatactuation is dependent upon the segment voltage applied. When anaddressing voltage is applied along a common line, application of onesegment voltage will result in a pixel voltage within a stabilitywindow, causing the pixel to remain unactuated. In contrast, applicationof the other segment voltage will result in a pixel voltage beyond thestability window, resulting in actuation of the pixel. The particularsegment voltage which causes actuation can vary depending upon whichaddressing voltage is used. In some implementations, when the highaddressing voltage VC_(ADD) _(—) _(H) is applied along the common line,application of the high segment voltage VS_(H) can cause a modulator toremain in its current position, while application of the low segmentvoltage VS_(L) can cause actuation of the modulator. As a corollary, theeffect of the segment voltages can be the opposite when a low addressingvoltage VC_(ADD) _(—) _(L) is applied, with high segment voltage VS_(H)causing actuation of the modulator, and low segment voltage VS_(L)having no effect (i.e., remaining stable) on the state of the modulator.

In some implementations, hold voltages, address voltages, and segmentvoltages may be used which always produce the same polarity potentialdifference across the modulators. In some other implementations, signalscan be used which alternate the polarity of the potential difference ofthe modulators. Alternation of the polarity across the modulators (thatis, alternation of the polarity of write procedures) may reduce orinhibit charge accumulation which could occur after repeated writeoperations of a single polarity.

FIG. 4A shows an example of a diagram illustrating a frame of displaydata in the 3×3 interferometric modulator display of FIG. 2. FIG. 4Bshows an example of a timing diagram for common and segment signals thatmay be used to write the frame of display data illustrated in FIG. 4A.The signals can be applied to the, e.g., 3×3 array of FIG. 2, which willultimately result in the line time 60 e display arrangement illustratedin FIG. 4A. The actuated modulators in FIG. 4A are in a dark-state,i.e., where a substantial portion of the reflected light is outside ofthe visible spectrum so as to result in a dark appearance to, e.g., aviewer. Prior to writing the frame illustrated in FIG. 4A, the pixelscan be in any state, but the write procedure illustrated in the timingdiagram of FIG. 4B presumes that each modulator has been released andresides in an unactuated state before the first line time 60 a.

During the first line time 60 a: a release voltage 70 is applied oncommon line 1; the voltage applied on common line 2 begins at a highhold voltage 72 and moves to a release voltage 70; and a low holdvoltage 76 is applied along common line 3. Thus, the modulators (common1, segment 1), (1,2) and (1,3) along common line 1 remain in a relaxed,or unactuated, state for the duration of the first line time 60 a, themodulators (2,1), (2,2) and (2,3) along common line 2 will move to arelaxed state, and the modulators (3,1), (3,2) and (3,3) along commonline 3 will remain in their previous state. With reference to FIG. 3B,the segment voltages applied along segment lines 1, 2 and 3 will have noeffect on the state of the interferometric modulators, as none of commonlines 1, 2 or 3 are being exposed to voltage levels causing actuationduring line time 60 a (i.e., VC_(REL)—relax and VC_(HOLD) _(—)_(L)—stable).

During the second line time 60 b, the voltage on common line 1 moves toa high hold voltage 72, and all modulators along common line 1 remain ina relaxed state regardless of the segment voltage applied because noaddressing, or actuation, voltage was applied on the common line 1. Themodulators along common line 2 remain in a relaxed state due to theapplication of the release voltage 70, and the modulators (3,1), (3,2)and (3,3) along common line 3 will relax when the voltage along commonline 3 moves to a release voltage 70.

During the third line time 60 c, common line 1 is addressed by applyinga high address voltage 74 on common line 1. Because a low segmentvoltage 64 is applied along segment lines 1 and 2 during the applicationof this address voltage, the pixel voltage across modulators (1,1) and(1,2) is greater than the high end of the positive stability window(i.e., the voltage differential exceeded a predefined threshold) of themodulators, and the modulators (1,1) and (1,2) are actuated. Conversely,because a high segment voltage 62 is applied along segment line 3, thepixel voltage across modulator (1,3) is less than that of modulators(1,1) and (1,2), and remains within the positive stability window of themodulator; modulator (1,3) thus remains relaxed. Also during line time60 c, the voltage along common line 2 decreases to a low hold voltage76, and the voltage along common line 3 remains at a release voltage 70,leaving the modulators along common lines 2 and 3 in a relaxed position.

During the fourth line time 60 d, the voltage on common line 1 returnsto a high hold voltage 72, leaving the modulators along common line 1 intheir respective addressed states. The voltage on common line 2 isdecreased to a low address voltage 78. Because a high segment voltage 62is applied along segment line 2, the pixel voltage across modulator(2,2) is below the lower end of the negative stability window of themodulator, causing the modulator (2,2) to actuate. Conversely, because alow segment voltage 64 is applied along segment lines 1 and 3, themodulators (2,1) and (2,3) remain in a relaxed position. The voltage oncommon line 3 increases to a high hold voltage 72, leaving themodulators along common line 3 in a relaxed state.

Finally, during the fifth line time 60 e, the voltage on common line 1remains at high hold voltage 72, and the voltage on common line 2remains at a low hold voltage 76, leaving the modulators along commonlines 1 and 2 in their respective addressed states. The voltage oncommon line 3 increases to a high address voltage 74 to address themodulators along common line 3. As a low segment voltage 64 is appliedon segment lines 2 and 3, the modulators (3,2) and (3,3) actuate, whilethe high segment voltage 62 applied along segment line 1 causesmodulator (3,1) to remain in a relaxed position. Thus, at the end of thefifth line time 60 e, the 3×3 pixel array is in the state shown in FIG.4A, and will remain in that state as long as the hold voltages areapplied along the common lines, regardless of variations in the segmentvoltage which may occur when modulators along other common lines (notshown) are being addressed.

In the timing diagram of FIG. 4B, a given write procedure (i.e., linetimes 60 a-60 e) can include the use of either high hold and addressvoltages, or low hold and address voltages. Once the write procedure hasbeen completed for a given common line (and the common voltage is set tothe hold voltage having the same polarity as the actuation voltage), thepixel voltage remains within a given stability window, and does not passthrough the relaxation window until a release voltage is applied on thatcommon line. Furthermore, as each modulator is released as part of thewrite procedure prior to addressing the modulator, the actuation time ofa modulator, rather than the release time, may determine the necessaryline time. Specifically, in implementations in which the release time ofa modulator is greater than the actuation time, the release voltage maybe applied for longer than a single line time, as depicted in FIG. 4B.In some other implementations, voltages applied along common lines orsegment lines may vary to account for variations in the actuation andrelease voltages of different modulators, such as modulators ofdifferent colors.

The details of the structure of interferometric modulators that operatein accordance with the principles set forth above may vary widely. Forexample, FIGS. 5A-5E show examples of cross-sections of varyingimplementations of interferometric modulators, including the movablereflective layer 14 and its supporting structures. FIG. 5A shows anexample of a partial cross-section of the interferometric modulatordisplay of FIG. 1, where a strip of metal material, i.e., the movablereflective layer 14 is deposited on supports 18 extending orthogonallyfrom the substrate 20. In FIG. 5B, the movable reflective layer 14 ofeach IMOD is generally square or rectangular in shape and attached tosupports at or near the corners, on tethers 32. In FIG. 5C, the movablereflective layer 14 is generally square or rectangular in shape andsuspended from a deformable layer 34, which may include a flexiblemetal. The deformable layer 34 can connect, directly or indirectly, tothe substrate 20 around the perimeter of the movable reflective layer14. These connections are herein referred to as support posts. Theimplementation shown in FIG. 5C has additional benefits deriving fromthe decoupling of the optical functions of the movable reflective layer14 from its mechanical functions, which are carried out by thedeformable layer 34. This decoupling allows the structural design andmaterials used for the reflective layer 14 and those used for thedeformable layer 34 to be optimized independently of one another.

FIG. 5D shows another example of an IMOD, where the movable reflectivelayer 14 includes a reflective sub-layer 14 a. The movable reflectivelayer 14 rests on a support structure, such as support posts 18. Thesupport posts 18 provide separation of the movable reflective layer 14from the lower stationary electrode (i.e., part of the optical stack 16in the illustrated IMOD) so that a gap 19 is formed between the movablereflective layer 14 and the optical stack 16, for example when themovable reflective layer 14 is in a relaxed position. The movablereflective layer 14 also can include a conductive layer 14 c, which maybe configured to serve as an electrode, and a support layer 14 b. Inthis example, the conductive layer 14 c is disposed on one side of thesupport layer 14 b, distal from the substrate 20, and the reflectivesub-layer 14 a is disposed on the other side of the support layer 14 b,proximal to the substrate 20. In some implementations, the reflectivesub-layer 14 a can be conductive and can be disposed between the supportlayer 14 b and the optical stack 16. The support layer 14 b can includeone or more layers of a dielectric material, for example, siliconoxynitride (SiON) or silicon dioxide (SiO₂). In some implementations,the support layer 14 b can be a stack of layers, such as, for example, aSiO₂/SiON/SiO₂ tri-layer stack. Either or both of the reflectivesub-layer 14 a and the conductive layer 14 c can include, e.g., an Alalloy with about 0.5% Cu, or another reflective metallic material.Employing conductive layers 14 a, 14 c above and below the dielectricsupport layer 14 b can balance stresses and provide enhanced conduction.In some implementations, the reflective sub-layer 14 a and theconductive layer 14 c can be formed of different materials for a varietyof design purposes, such as achieving specific stress profiles withinthe movable reflective layer 14.

As illustrated in FIG. 5D, some implementations also can include a blackmask structure 23. The black mask structure 23 can be formed inoptically inactive regions (e.g., between pixels or under posts 18) toabsorb ambient or stray light. The black mask structure 23 also canimprove the optical properties of a display device by inhibiting lightfrom being reflected from or transmitted through inactive portions ofthe display, thereby increasing the contrast ratio. Additionally, theblack mask structure 23 can be conductive and be configured to functionas an electrical bussing layer. In some implementations, the rowelectrodes can be connected to the black mask structure 23 to reduce theresistance of the connected row electrode. The black mask structure 23can be formed using a variety of methods, including deposition andpatterning techniques. The black mask structure 23 can include one ormore layers. For example, in some implementations, the black maskstructure 23 includes a molybdenum-chromium (MoCr) layer that serves asan optical absorber, a SiO₂ layer, and an aluminum alloy that serves asa reflector and a bussing layer, with a thickness in the range of about30-80 Å, 500-1000 Å, and 500-6000 Å, respectively. The one or morelayers can be patterned using a variety of techniques, includingphotolithography and dry etching, including, for example, CF₄ and/or O₂for the MoCr and SiO₂ layers and Cl₂ and/or BCl₃ for the aluminum alloylayer. In some implementations, the black mask 23 can be an etalon orinterferometric stack structure. In such interferometric stack blackmask structures 23, the conductive absorbers can be used to transmit orbus signals between lower, stationary electrodes in the optical stack 16of each row or column. In some implementations, a spacer layer 35 canserve to generally electrically isolate the absorber layer 16 a from theconductive layers in the black mask 23.

FIG. 5E shows another example of an IMOD, where the movable reflectivelayer 14 is self supporting. In contrast with FIG. 5D, theimplementation of FIG. 5E does not include support posts 18. Instead,the movable reflective layer 14 contacts the underlying optical stack 16at multiple locations, and the curvature of the movable reflective layer14 provides sufficient support that the movable reflective layer 14returns to the unactuated position of FIG. 5E when the voltage acrossthe interferometric modulator is insufficient to cause actuation. Theoptical stack 16, which may contain a plurality of several differentlayers, is shown here for clarity including an optical absorber 16 a,and a dielectric 16 b. In some implementations, the optical absorber 16a may serve both as a fixed electrode and as a partially reflectivelayer.

In implementations such as those shown in FIGS. 5A-5E, the IMODsfunction as direct-view devices, in which images are viewed from thefront side of the transparent substrate 20, i.e., the side opposite tothat upon which the modulator is arranged. In these implementations, theback portions of the device (that is, any portion of the display devicebehind the movable reflective layer 14, including, for example, thedeformable layer 34 illustrated in FIG. 5C) can be configured andoperated upon without impacting or negatively affecting the imagequality of the display device, because the reflective layer 14 opticallyshields those portions of the device. For example, in someimplementations a bus structure (not illustrated) can be included behindthe movable reflective layer 14 which provides the ability to separatethe optical properties of the modulator from the electromechanicalproperties of the modulator, such as voltage addressing and themovements that result from such addressing. Additionally, theimplementations of FIGS. 5A-5E can simplify processing, such as, e.g.,patterning.

FIG. 6 shows an example of a flow diagram illustrating a manufacturingprocess 80 for an interferometric modulator, and FIGS. 7A-7E showexamples of cross-sectional schematic illustrations of correspondingstages of such a manufacturing process 80. In some implementations, themanufacturing process 80 can be implemented to manufacture, e.g.,interferometric modulators of the general type illustrated in FIGS. 1and 5, in addition to other blocks not shown in FIG. 6. With referenceto FIGS. 1, 5 and 6, the process 80 begins at block 82 with theformation of the optical stack 16 over the substrate 20. FIG. 7Aillustrates such an optical stack 16 formed over the substrate 20. Thesubstrate 20 may be a transparent substrate such as glass or plastic, itmay be flexible or relatively stiff and unbending, and may have beensubjected to prior preparation processes, e.g., cleaning, to facilitateefficient formation of the optical stack 16. As discussed above, theoptical stack 16 can be electrically conductive, partially transparentand partially reflective and may be fabricated, for example, bydepositing one or more layers having the desired properties onto thetransparent substrate 20. In FIG. 7A, the optical stack 16 includes amultilayer structure having sub-layers 16 a and 16 b, although more orfewer sub-layers may be included in some other implementations. In someimplementations, one of the sub-layers 16 a, 16 b can be configured withboth optically absorptive and conductive properties, such as thecombined conductor/absorber sub-layer 16 a. Additionally, one or more ofthe sub-layers 16 a, 16 b can be patterned into parallel strips, and mayform row electrodes in a display device. Such patterning can beperformed by a masking and etching process or another suitable processknown in the art. In some implementations, one of the sub-layers 16 a,16 b can be an insulating or dielectric layer, such as sub-layer 16 bthat is deposited over one or more metal layers (e.g., one or morereflective and/or conductive layers). In addition, the optical stack 16can be patterned into individual and parallel strips that form the rowsof the display.

The process 80 continues at block 84 with the formation of a sacrificiallayer 25 over the optical stack 16. The sacrificial layer 25 is laterremoved (e.g., at block 90) to form the cavity 19 and thus thesacrificial layer 25 is not shown in the resulting interferometricmodulators 12 illustrated in FIG. 1. FIG. 7B illustrates a partiallyfabricated device including a sacrificial layer 25 formed over theoptical stack 16. The formation of the sacrificial layer 25 over theoptical stack 16 may include deposition of a xenon difluoride(XeF₂)-etchable material such as molybdenum (Mo) or amorphous silicon(Si), in a thickness selected to provide, after subsequent removal, agap or cavity 19 (see also FIGS. 1 and 7E) having a desired design size.Deposition of the sacrificial material may be carried out usingdeposition techniques such as physical vapor deposition (PVD, e.g.,sputtering), plasma-enhanced chemical vapor deposition (PECVD), thermalchemical vapor deposition (thermal CVD), or spin-coating.

The process 80 continues at block 86 with the formation of a supportstructure e.g., a post 18 as illustrated in FIGS. 1, 5 and 7C. Theformation of the post 18 may include patterning the sacrificial layer 25to form a support structure aperture, then depositing a material (e.g.,a polymer or an inorganic material, e.g., silicon oxide) into theaperture to form the post 18, using a deposition method such as PVD,PECVD, thermal CVD, or spin-coating. In some implementations, thesupport structure aperture formed in the sacrificial layer can extendthrough both the sacrificial layer 25 and the optical stack 16 to theunderlying substrate 20, so that the lower end of the post 18 contactsthe substrate 20 as illustrated in FIG. 5A. Alternatively, as depictedin FIG. 7C, the aperture formed in the sacrificial layer 25 can extendthrough the sacrificial layer 25, but not through the optical stack 16.For example, FIG. 7E illustrates the lower ends of the support posts 18in contact with an upper surface of the optical stack 16. The post 18,or other support structures, may be formed by depositing a layer ofsupport structure material over the sacrificial layer 25 and patterningportions of the support structure material located away from aperturesin the sacrificial layer 25. The support structures may be locatedwithin the apertures, as illustrated in FIG. 7C, but also can, at leastpartially, extend over a portion of the sacrificial layer 25. As notedabove, the patterning of the sacrificial layer 25 and/or the supportposts 18 can be performed by a patterning and etching process, but alsomay be performed by alternative etching methods.

The process 80 continues at block 88 with the formation of a movablereflective layer or membrane such as the movable reflective layer 14illustrated in FIGS. 1, 5 and 7D. The movable reflective layer 14 may beformed by employing one or more deposition steps, e.g., reflective layer(e.g., aluminum, aluminum alloy) deposition, along with one or morepatterning, masking, and/or etching steps. The movable reflective layer14 can be electrically conductive, and referred to as an electricallyconductive layer. In some implementations, the movable reflective layer14 may include a plurality of sub-layers 14 a, 14 b, 14 c as shown inFIG. 7D. In some implementations, one or more of the sub-layers, such assub-layers 14 a, 14 c, may include highly reflective sub-layers selectedfor their optical properties, and another sub-layer 14 b may include amechanical sub-layer selected for its mechanical properties. Since thesacrificial layer 25 is still present in the partially fabricatedinterferometric modulator formed at block 88, the movable reflectivelayer 14 is typically not movable at this stage. A partially fabricatedIMOD that contains a sacrificial layer 25 may also be referred to hereinas an “unreleased” IMOD. As described above in connection with FIG. 1,the movable reflective layer 14 can be patterned into individual andparallel strips that form the columns of the display.

The process 80 continues at block 90 with the formation of a cavity,e.g., cavity 19 as illustrated in FIGS. 1, 5 and 7E. The cavity 19 maybe formed by exposing the sacrificial material 25 (deposited at block84) to an etchant. For example, an etchable sacrificial material such asMo or amorphous Si may be removed by dry chemical etching, e.g., byexposing the sacrificial layer 25 to a gaseous or vaporous etchant, suchas vapors derived from solid XeF₂ for a period of time that is effectiveto remove the desired amount of material, typically selectively removedrelative to the structures surrounding the cavity 19. Other etchingmethods, e.g. wet etching and/or plasma etching, also may be used. Sincethe sacrificial layer 25 is removed during block 90, the movablereflective layer 14 is typically movable after this stage. After removalof the sacrificial material 25, the resulting fully or partiallyfabricated IMOD may be referred to herein as a “released” IMOD.

Reflective displays, such as reflective displays comprisinginterferometric modulators such as the implementation shown in FIG. 7E,may reflect ambient light towards a viewer thereby providing the viewerwith a displayed image. However, in some circumstances, reflectivedisplays such as the display 810 shown in FIG. 8A, may requireadditional illumination to properly display an image. FIG. 8A is anillustration of a display being illuminated by an illumination device. Areflective display, such as an interferometric modular display or otherreflective display, may require an illumination device 820 to illuminatethe display 810 in order for the image to be seen by a viewer. This maybe desirable when ambient light, even if present, is not sufficient tofully illuminate the display. In some implementations, illuminationdevice 820 may include a front light with turning features to turn lightguided within the light guide towards the display 810 allowing theturned light to reflect off of the display 810 towards the viewer. Lightmay be injected into light guide 820 by one or more LEDs coupled to theillumination device 820 (LED(s) not shown). Alternatively, in some otherimplementations, an LED may be coupled into an edge bar (not shown)which may then spread the light along the width of light guide 820 to beguided within light guide 820 and then ejected towards the display 810to illuminate the display 810.

In some implementations, it may be desirable to additionally includetouch sensor capability for a display device 800, as shown in theimplementation of FIG. 8B. FIG. 8B is an example of an illustration of adisplay with an illumination device and a touch sensor. As shown in theimplementation of FIG. 8B, display 810 is illuminated with illuminationdevice 820. Stacked over the illumination device is touch sensor 830.Touch sensor 830 is capable of determining the location of a touch bysensing a change to the capacitance of a conductor formed in the touchsensor 830, wherein the change to the capacitance of the conductor isinduced by the proximity of a human finger 835. The use of touch sensor830 with illumination device 820 allows for the useful interaction ofthe user's finger with the display device 800. For example, by touchingthe screen in different locations, the user may use his or her finger835 to select a certain icon 837 displayed on the display 810 of thedisplay device 800. In some implementations, illumination device 820 isnot integrated with touch sensor 830. Therefore, illumination device 820and touch sensor 830 are mechanically stacked one on top of the other.As shown in FIG. 8B, touch sensor 830 is stacked over the illuminationdevice 820, however, in other implementations, the illumination device820 may be stacked over the touch sensor 830. As shown, the touch sensor830 is closer to the user viewing the display 810. In yet otherimplementations, the touch sensor 830 may be behind the display 810.

With reference to FIG. 8C, an example of an illustration of animplementation of a display with an integrated illumination device withtouch sensor is shown. FIG. 8C shows an illumination device integratedwith touch sensor 840 formed over a display 810, the illumination deviceintegrated with touch sensor 840 being closer to the viewer than display810 on the side of the display 810 that displays an image, i.e., animage-displaying side. The illumination device integrated with touchsensor 840 can simultaneously illuminate the reflective display 810 toprovide for illumination while also allowing for touch sensorcapability. In various implementations, one or more components of theillumination device integrated with touch sensor 840 simultaneously haveillumination as well as touch-sensing function. For example, conductorsformed in the illumination device integrated with touch sensor 840 mayprovide both illumination capabilities as well as touch-sensingcapabilities as will be described in greater detail below. Asillustrated, illumination device integrated with touch sensor 840includes one unit or layer. However, it is understood that theillumination device integrated with touch sensor 840 may includemultiple layers and components.

In some implementations, illumination device integrated with touchsensor 840 may be capable of determining whether or not a human finger835 has touched or come into sufficiently close contact with theillumination device integrated with touch sensor 840 so as to effect thecapacitance of conductors at least one of which is formed in theillumination device integrated with touch sensor 840. In variousimplementations, illumination device integrated with touch sensor 840 iscapable of determining a location in x-y coordinates of one or moretouches onto the illumination device integrated with touch sensor 840 bya human finger 835. The one or more touches on illumination deviceintegrated with touch sensor 840 by a human finger 835 may besimultaneous or temporally isolated. One way of integrating illuminationdevice 820 and touch sensor 830 of FIG. 8B to form an implementation asillustrated in FIG. 8C is to use metalized turning features in theillumination device 820 while simultaneously using the metalizedlight-turning features of the illumination device as conductors inelectrical communication with an touch-sensing electrode system. Thetouch-sensing electrode system may be capable of sensing a change to acapacitance of the conductor induced by the proximity of a human finger835.

With reference to FIG. 9A, an example of an illustration of animplementation of a light guide is shown. FIG. 9A depicts animplementation of an illumination device 820 comprising light-turningfeatures 901 a, 901 b, 901 c. Such features can “turn” light propagatingin light guide 820 out of the light guide and toward a display 810. Asshown in FIG. 9A, light-turning features 901 a, 901 b, 901 c includefacets 905 that can reflect or turn light. Also as shown in FIG. 9A,light-turning features 901 a, 901 b, 901 c can include multipledifferent shapes. For example, light-turning features 901 a, 901 b, 901c may extend longitudinally in one direction, for example, the xdirection, as illustrated in feature 901 a. In other implementations,the light-turning features 901 a, 901 b, 901 c may include a featurewhich is discrete, such as 901 b and 901 c. Also light-turning features901 a, 901 b, 901 c may include pyramidal, conical or trapezoidalfeatures or other features or cross-sectional profiles capable ofejecting a light ray 902 a, 902 b, 902 c, toward a display 810.Illumination devices similar to illumination device 820 can be useful inilluminating a display 810 from the front and are often referred to as a“front light.”

In some implementations, it may be useful to form metal conductors onlight-turning features 901 a, 901 b, 901 c. A person/one having ordinaryskill in the art will understand that light-turning features may includevarious types of structures, e.g., diffractive and reflectivestructures, that redirect light. In some implementations, thelight-turning features are reflective, with the reflections occurring onsurfaces of the light-turning features. These surfaces are commonlyreferred to as facets. In some implementations, light-turning feature901 a, 901 b, or 901 c may be defined by a recess in the light guide820, with the surfaces of the recess constituting one or more facets905. Light impinging on the facet 905 may be reflected or may passthrough the facet depending upon the angle of incidence of the light.For example, as shown by light ray 902 a, a light ray propagating inillumination device 820 may sometimes be incident upon a surface of afacet 905 in a light-turning feature 901 a, 901 b, 901 c at an anglethat is less than the critical angle (shown in FIG. 9A as θ_(c)), asmeasured relative to the normal to the facet that the light is incident.As will be understood by those of skill in the art, in such cases lightray 902 a may exit the illumination device 820 as shown in escaped lightray 904. Such light is wasted since it is not directed towards display810 and is therefore not used to illuminate display 810. Indeed, suchlight will degrade the image of the display 810. It is thereforedesirable to construct a light-turning feature 901 a, 901 b, 901 c whichwill reflect light even if light ray 902 a is incident uponlight-reflecting facet 905 at an angle that is less than the criticalangle. Such a light-turning feature may be formed by forming a metalconductor on the surface of facet 905 thereby “metalizing” the surfaceof facet 905.

With reference to FIG. 9B, an example of an illustration of animplementation of a light guide with metalized light-turning features isshown. In FIG. 9B, illumination device 910 includes a light guidecomprising a conductor 915 formed on a facet of a light-turning featureto form metalized light-turning features 920. Although all of themetalized light-turning features 920 in FIG. 9B are shown fullymetalized, it is understood that a metalized light-turning feature 920need not be completely metalized. For example, a light-turning featurethat extends as a long groove (such as, light-turning feature 901 a inFIG. 9A) may only be metalized at certain points along the groove (i.e.,the x direction), and not along the entirety of the groove. In addition,some light-turning features can be partly and/or completely metalizedwhile others are not metalized. In some implementations, conductor 915is a reflective or specular metal conductor. As explained above,metalized light-turning features 920 may confer certain advantages overlight-turning features that are not metalized. As will be understood bythose of skill in the art, the problem discussed above in relation toFIG. 9A of a light ray incident upon a facet of a light-turning featureat an angle below the critical angle is exacerbated when additionallayers (with index higher than air) are stacked over a glass or otherhigh index light guide since the low-index layers will increase thecritical angle for total internal reflection. This increase in thecritical angle will reduce the range of rays ejected by non-metalizedlight-turning features.

With reference to FIG. 9C, an example of a cross-sectional view of animplementation of a light guide with metalized light-turning featureswith integrated touch sensor is shown. FIG. 9C depicts an implementationof an illumination device with conductive features integrated into themetalized light-turning features 920. While shown as having a v-likecross-section, it is understood that metalized light-turning features920 may have various shapes, such as a tapered cylinder or other shapehaving facets angled to direct light downwards, as indicated, forexample, by reference numerals 901 a, 901 b, and 901 c of FIG. 9A. Theillumination device includes a light guide 910 comprising metalizedlight-turning features 920 having light-reflecting conductors 915 formedon a light-turning feature. The illumination device also includestouch-sensing electronics 930 which are electrically connected tolight-reflecting conductors 915 and electrodes 950. In someimplementations, the light-reflecting conductors 915 may be part of alight-turning feature 920 over the entire length of the light-turningfeature 920, or may only extend part of the length of the light-turningfeatures 920, or may extend farther than the length of light-turningfeatures 920. The touch-sensing electronics 930 may be connected to someof the light-reflecting conductors 915, while other light-reflectingconductors 915 are not electrically connect to the touch-sensingelectronics 930. In some other implementations, as illustrated,neighboring light-reflecting conductors 915 may be electricallyconnected to touch-sensing electronics 930. Additionally, FIG. 9Cdepicts additional layers formed over the light guide 910. In additionto overcoming problems affiliated with nonmetalized light-turningfeatures as described above, the conductors 915 formed over facets 905of the light-turning feature 920 may additionally be exploited by beingin electrical communication with an electronic system. The conductors915 may extend partly or completely across a display surface, e.g.,completely across the viewable surface of a display. In someimplementations, the electronic system includes touch-sensingelectronics 930 and the conductors 915 form part of a touch-sensingelectrode system. The touch-sensing electrode system may but do notnecessarily include a plurality of conductors 915 that are part ofmetalized light-turning features and a plurality of conductors that arenot part of any light-turning feature (which may collectively bereferred to as “electrodes”) in electrical communication withtouch-sensing electronics 930. Touch-sensing electronics 930 may becapable of detecting a change to a capacitance of the conductor 915induced by the proximity of a conductive body, for example, a humanfinger 835, and hence the electrode system as a whole is capable ofdetecting a change to a capacitance of the conductor 915 induced by theproximity of a human finger 835. Using conductors 915 formed on alight-turning feature also as part of a capacitive touch sensor allowsfor integrating touch-sensor capability with a light guide.

In the implementation illustrated in FIG. 9C, the illumination deviceintegrated with touch sensor capability 840 includes layers over lightguide 910, i.e., opposite the light guide 910 from the display 810. Forexample, layer 940 may be a dielectric layer to electrically isolateconductors 915 from electrode 950 (with electrode 950 extending alongthe y direction). While only one electrode 950 is shown in thecross-sectional view of FIG. 9C, some implementations may include manyelectrodes like electrode 950 in parallel extending along the ydirection orthogonal to conductors 915. In some implementations, layer940 may include silicone or other non-corrosive dielectric.Non-corrosive materials are preferred, so as not to degrade or corruptconductors 915. In some implementations layer 940 may be a pressuresensitive adhesive (PSA) layer that is pressed onto or over light guide910. Layer 940 may serve other purposes, for example, in implementationswithout electrodes 950 (see, for example, the implementation of FIG.10C). Layer 940 may have an index of refraction higher than that of airbut lower than about 1.5, or lower than about 1.4, or lower than about1.35, and therefore, layer 940 formed over light guide 910 may increasethe critical angle for light guided in light guide 910. In someimplementations, the layer 940 may have an index of refraction of, forexample, 1.2 or 1.3. As described above, this may have a negative effecton the turning capability of light-turning features (non-metalized).However, reflective conductors 915 may help reduce these liabilities,and may therefore allow for greater flexibility in designing layers overlight guide 910. Additionally, illumination device integrated with touchsensor capability 840 may include other layers, such as passivationlayer 960.

With reference to FIG. 9D, an example of an illustration of across-sectional view of an implementation with metalized-light-turningfeatures and touch-sensing electrodes is shown. The implementation ofFIG. 9D is similar to the implementation of FIG. 9C, except that thetouch-sensing electronics 930 is not electrically connected to themetalized light-turning features 920. In such an implementation, touchsensing may be accomplished using a grid of electrodes like electrodes950 (extending in the y direction) and 955 (extending in the xdirection, out of the page). It is understood that, alternatively, thetouch-sensing electrode may not be a grid, as, for example, in theimplementation of FIG. 10C, and hence may only include electrodes 955(in which case electrodes 955 may include discrete electrodes) withoutelectrodes 950. Such an implementation may be manufactured usingrelatively few steps, where electrodes 955 and metalized light-turningfeatures 920 are deposited and etched using the same process, asdescribed in greater detail below. In some other implementations, thetouch-sensing electronics 930 can be electrically connected to both themetalized light-turning features 920 and the electrodes 955, in additionto being electrically connected to the electrodes 950, or without beingelectrically connected to the electrodes 950. In some implementations,only some of the metalized light-turning features 920 are connected tothe touch-sensing electronics 930.

With reference to FIG. 10A, an example of an illustration of animplementation of a touch sensor is shown. The touch sensor may be acapacitive touch sensor. In general, and as depicted in theimplementation of FIG. 10A, the capacitive touch sensor includesconductors which serve as electrodes 1010, 1020. As depicted in theimplementation of FIG. 10A, electrodes 1010 extend in the x direction,while electrodes 1020 extend in the y direction. If a current is passedin one of electrodes 1010 or electrodes 1020, an electric field,illustrated in FIG. 10A by field lines 1030, may form between electrodes1010 and electrodes 1020. The electric fields formed between electrodes1010 and 1020 are related to a mutual capacitance 1035 a and 1035 b.When a human finger 835, or any other conductive body or object, isbrought in the proximity of electrodes 1010 or 1020, charges present inthe tissues and blood of the finger may change or affect the electricfield formed between electrodes 1010 and 1020. This disturbance of theelectric field may affect the mutual capacitance and can be measured ina change in the mutual capacitance 1035 a, 1035 b, which may be sensedby touch-sensing electronics 930. The conductors 915 of FIG. 9C maysimultaneously serve the optical functions described elsewhere hereinand may serve as electrodes 1010 or 1020 depicted in FIGS. 10A and 10Bor electrodes 1040 in FIG. 10C. FIGS. 10B-10C are examples ofillustrations of implementations of illumination devices with anintegrated touch sensor.

With reference to FIG. 10B, it is understood that in an illuminationdevice integrated with touch sensor 840, layer 1050 or 1052 may, in someimplementations, include a light guide with metalized light-turningfeatures that include some of or a part of electrodes 1020 or 1010. Inimplementations where layer 1052 is a light guide, electrodes 1020formed beneath layer 1052, i.e., between layer 1052 and display 810, maybe transparent or semi-transparent and include a transparent conductor.Similarly, in some implementations, layer 1053 may include a light guidewith metalized light-turning features that include some of or a part ofelectrodes 1010.

With reference to FIG. 10B, in some implementations, layer 1050 includesa light guide and at least some of or a part of electrodes 1020 includeat least some metalized light-turning features formed in layer 1050.Electrodes 1020, including metalized light-turning features, may beformed by a deposition and patterning process. In some implementations,electrodes 1010 formed on layer 1052 may be laminated or bonded ontolayer 1050 for convenience and ease of manufacturing.

If the electrodes are in known x-y locations, then the x-y location of atouch by the finger on the touch sensor 830 may also be determined. Forexample, a touch sensor may include a multitude of electrodes extendingin the x direction and a multitude of electrodes extending lengthwise inthe y direction and/or periodic in the x direction, as shown in FIG.10B. The touch-sensing electronics 930 may be capable of isolating orlocating or determining x direction electrodes and y directionelectrodes that register a change in their mutual capacitances therebydetermining the x-y coordinates of the touch. It is understood that a“touch” may include a single touch or multiple touches, whethersimultaneous or at different times. “Touch” may also include strokes. Itis to be understood that other parts of a human body may be used otherthan a finger for touching the touch screen. A stylus or any toolcapable of affecting the mutual or self capacitance of any electrodesystem by being in proximity to such system may also be used, such as aconducting body capable of affecting the mutual or self capacitance.Such a tool may be used to touch a display device in order tocommunicate or input data into a machine using display devicesimultaneously as an output and as an input device.

In the implementation of FIGS. 10A and 10B, the sensing electronics 930may sense the mutual capacitance between electrodes 1010 extending inthe x direction and electrodes 1020 extending in the y direction.However, in other implementations, only one level of conductors orelectrodes may be used, as illustrated in FIG. 10C. In such animplementation, touch-sensing electronics 930 may be in electricalcommunication with a series of conductors (electrodes 1040 in FIG. 10C)on a touch sensor and may be capable of measuring the self capacitanceof the conductors in the touch sensor. The self capacitance is theamount of electrical charge that is added to an isolated conductor toraise its electric potential by one volt. The proximity of a humanfinger may affect this self capacitance. Touch-sensing electronics 930may be configured to sense the change in self capacitance. Therefore, insome implementations, a touch sensor may not require a grid of X and Yelectrodes but may simply require an array of discrete electrodes 1040(conductors) dispersed in both the X and y direction at known x-ycoordinates. As noted above in relation to FIG. 10B, it is understoodthat in an illumination device integrated with touch sensor 840, layer1050 may, in some implementations, include a light guide with metalizedlight-turning features that include some of or a part of electrodes1040. Similarly, in some implementations, layer 1053 may include a lightguide with metalized light-turning features that include a part ofelectrodes 1040. In the illustrated implementation, illumination deviceintegrated with touch sensor 840 is disposed in front of display 810 andfunctions as a front light.

With reference to FIG. 11A, an example of an illustration of animplementation of a light guide with metalized light-turning featuresintegrated with a touch sensor is shown. FIG. 11A depicts a light guidehaving light-turning features 901 capable of directing light propagatingin the light guide 910 towards a display 810. As shown in FIG. 11A, somelight-turning features 901 are left unmetalized while others aremetalized light-turning features 920 a, 920 b. It is noted that whilemetalized light-turning feature 920 b is illustrated as completelymetalized in order to maximize the light-turning ability of the feature,it is noted that some implementations may include light-turning featureswith surfaces or facets that are not completely metalized. As also shownin the implementation of FIG. 11A, an auxiliary structure 1105 can beformed on the same level as the metalized light-turning features 920 a,920 b. As shown in FIG. 11A, the auxiliary structure 1105 includes aconductive line. More generally, auxiliary structures can be formed ofthe same material as the metallization of the metalized light-turningfeatures 920, e.g., by depositing the metallization on the surface ofthe light guide 910 and then patterning the layer of deposited materialto simultaneously define the metallization of the metalizedlight-turning features 920 a, 920 b and to form the auxiliary structure1105. In some implementations, the auxiliary structure 1105 is aconductive line and the metalized light-turning feature 920 b isconnected to a touch-sensing electrode system (i.e. electricallyconnected to other electrodes and conductors and to touch-sensingelectronics 930) by the conductive line. The conductive line 1105 mayinclude a reflective metal line that connects the conductor of metalizedlight-turning feature 920 b with an electrode system capable of sensinga change to a capacitance of the conductor induced by the proximity of ahuman finger. In other implementations, conductive line 1105 may includea transparent conductor such as indium tin oxide (ITO). As shown in FIG.11A, not all metalized light-turning features need be integrated or inelectrical communication with the touch-sensing electrode system. Forexample, in order to achieve a desired illumination of a display 810,light-turning features of a certain size and/or density may beadvantageous. For example, for a light-turning feature of about 3-30 umsize, in some implementations, about 1,000-100,000 features per squarecm of light guide may be used. However, given the dimensions of a humanfinger, the density of conductors in electrical communication with atouch sensing electrode system may be much less. For example, thespacing between electrodes, including metalized light-turning featuresthat are part of the electrode system, may be roughly greater than oneper square centimeter. However, the spacing between electrodes may beless in applications where precision is less important. Similarly, thespacing between electrodes may be greater in other applications wherehigh precision is important. Depending upon the density of metalizedlight-turning features, in some implementations, one in ten, or less,metalized light-turning features may be in electrical communication withthe touch-sensing electrode system. Therefore, in some implementations,the number of metalized light-turning features 920 in electricalcommunication with the touch-sensing electrode system may be far fewerthan the number of metalized light-turning features 920. Furthermore, asshown in FIG. 11A, not all light-turning features need be metalized.Also, as shown in FIG. 11A, some light-turning features 920 a arecompletely metalized, while others (e.g., metalized light-turningfeature 920 b) are only partially metalized.

In implementations where conductive line 1105 includes a reflectivemetallic line, reflections of ambient light may occur that may degradethe image formed on display 810. For example, as shown in FIG. 11A,ambient light ray 1110 may be incident on conductive line 1105, and mayreflect back towards the viewer. These reflections of ambient light maydegrade the image displayed on the display as reflected white light maywhiten out the (colored) light that is reflected from the display,illustrated as rays 1115 in FIG. 11A. Similar reflections from metalizedlight-turning features 920 may similarly degrade an image displayed ondisplay 810. These reflections of ambient light may, as will beunderstood by those of skill in the art, lead to contrast ratioreduction. Therefore, it is desirable to mask reflections by metallicsurfaces, such as metalized light-turning features 920 or metallicconductive lines 1105. One way to accomplish this is to coat metallicsurfaces with a thin film interferometric structure in order to reduceor eliminate the reflections that would otherwise lead to contrast ratioreduction.

With reference to FIG. 11B, an example of an illustration of animplementation of a light guide with layers of material deposited on thesurfaces of light-turning features and structures composed of thoselayers formed outside of the light-turning features is shown. FIG. 11Bdepicts a conductor formed on a light-turning feature to produce ametalized light-turning feature 920, however, additionally, themetalized light-turning feature is masked to reduce or eliminatereflections of ambient light using a thin film interferometric structure1120. Since the reflective conductor may contribute to theinterferometric effect, the thin film interferometric structure 1120 mayalso be said to include conductor 915 (or conductive line 1105). Thethin film interferometric structure 1120 includes a spacer layer 1130,which can be a dielectric or conductive layer in some implementations,and a thin metal or metal alloy absorber 1135. The spacer layer 1130 hasa thickness, and may include various suitable transparent materials forforming an “optical resonant cavity.” The spacer layer 1130 (“opticalresonant cavity”) may be formed between the conductor 915 (or conductiveline 1105) and the absorber 1135. The spacer layer 1130 may includematerials such as air (e.g. using posts to hold up absorber layer 1135),Al₂O₃, SiO₂, TiO₂, ITO, Si₃N₄, Cr₂O₃, ZnO, or mixtures thereof.Depending on the thickness of the spacer layer 1130, the interferometricstructure 1120 may reflect a color such as red, blue, or green, or inother implementations, the thickness of the spacer layer 1130 may beadjusted so as to provide for little or no reflection (e.g., black). Asuitable thickness for spacer layer 1030 (other than air) is between 300Å and 1000 Å to produce an interferometric dark or black effect. Methodsof depositing or forming dielectric layers are known in the art,including CVD, as well as other methods. In another implementation,where the spacer layer 1030 is a dielectric or insulator, the spacerlayer 1030 may be formed with an air gap or other transparent dielectricmaterial. A suitable thickness for an air gap dielectric layer 1030 isbetween 450 Å and 1600 Å to produce an interferometric dark or blackeffect. Other thickness ranges may be used, for example, to achieveother colors such as red, blue, or green.

Also shown in FIG. 11B, formed over the spacer layer 1130 is a metallicabsorber 1135. In the illustrated implementation where theinterferometric structure 1120 is designed to interferometrically darkenthe appearance of the naturally reflective conductor 915 formed on themetalized light-turning feature 920 or the conductive line 1105, theabsorber 1135 may include, for example, semi-transparent thicknesses ofmetallic or semiconductor layers. The absorber 1135 may also includematerials that have a non-zero n*k, i.e., a non-zero product of theindex of refraction (n) and the extinction coefficient (k). Inparticular, chromium (Cr), molybdenum (Mo), titanium (Ti), silicon (Si),tantalum (Ta), and tungsten (W) all may form suitable layers. Othermaterials may be employed. In one implementation, the thickness of theabsorber 1135 is between 20 Å and 300 Å. In one implementation, theabsorber 1135 is less than 500 Å, although thicknesses outside theseranges may be employed. As shown in FIG. 11B, in some implementations,interferometric structure 1120 may also be formed over a conductive line1105.

While the interferometric structure 1120 formed over conductive line1105 or metalized light-turning feature 920 allows for little or noreflection of ambient light towards a viewer, for light propagatingwithin light guide 910, the reflective metalized surface of conductorscan reflect light that is guided within the light guide as desired. Forexample, light traveling within the light guide may reflect off of themetallic surface of the conductive line 1105 in such a way so as tocontinue being guided within the light guide 910, as shown by light rays1140 a and 1140 b. The metal layer 1105 may be about 30-100 nm thick insome implementations. Examples of high reflectivity metals for the metallayer 1105 include Al, Al alloys, Ag, etc. Similarly, light guidedwithin the light guide may reflect off of the metalized light-turningfeature 920 so as to be reflected towards a display to be illuminated810. For example, light ray 1143 a and 1146 a are incident upon thereflective conductor comprising metalized light-turning feature 920 andreflected towards the display 810 to be illuminated as shown by rays1143 b and 1146 b. While illustrated in the implementation of FIG. 11Bas preventing reflections of ambient light from metalized light-turningfeatures 920 or conductive line 1105, it is understood thatinterferometric structure 1120 may be formed over any reflective surfaceformed forward of, i.e. closer to a viewer than or on animage-displaying side of, a display 810. As such, for any reflectivesurface formed on an illumination device, a capacitive touch sensor, orother device formed forward of a display, an interferometric structure1120 may be used to reduce reflections of ambient light so as not todegrade the image on the display. Such reflective conductors may beformed on any component configured to be placed on an image-displayingside of a display, for example, a front light formed over a display, atouch sensor formed over a display, or other device formed forward of adisplay.

As shown in FIG. 11B, auxiliary structure 1105, which may be aconductive line, may be formed on a surface, e.g., the top surface, ofthe light guide 910, while the conductor 915 is formed in alight-turning feature. As illustrated, the light-turning featureincludes a recess formed on the top surface of the light guide 910 andextends down into the light guide 910. The recess can have facetedsurfaces for turning light. The conductor 915 formed in thelight-turning feature thereby forms a metalized light-turning feature920. Conductive line 1105 and metalized light-turning feature 920 may beefficiently manufactured by depositing a reflective, conductingmaterial, e.g., a metal, on a top surface (including conformallydepositing the material in the recesses of the light-turning featuresformed on the top surface) of the light guide 910 and etching thematerial to form the conductive line 1105 and leaving some of thematerial in the recess of the light-turning feature to form themetalized light-turning feature 920. In other words, an auxiliarystructure such as the conductive line 1105 and the metallization in therecesses forming the light-turning features may be formed simultaneouslyin a single patterning step; it may not be necessary to form conductiveline 1105 and metalized light-turning feature 920 in separate steps.This may be accomplished on a light guide comprising a substrate, or alight guide comprising an index-matched turning film formed on anoptically transparent substrate.

More generally, the conductive line 1105 illustrated in FIG. 11B mayform part of passive and/or active electronic devices. For example, asdiscussed herein, the line 1105 may be a conductive line 1105 such as anelectrode. In other implementations, it is possible to deposit manydifferent kinds of materials other than metals on the top surface of thelight guide. For example, the deposited material may includesemi-conductor materials, including a highly reflective semi-conductingmaterial, or a dielectric, or a combination of materials havingdifferent electrical properties. In such a way, a single deposition of aparticular material may be used to form an auxiliary structure (shown inFIG. 11B as a conducting line 1105) on a top surface of a light guide aswell as to coat the recess of a light-turning feature formed on the topsurface. Similarly, etching the material to form an auxiliary structureand simultaneously leaving some of the material in the recesses of thelight-turning features to form material-filled or coated light-turningfeatures may be accomplished using a single patterning process, such asa photolithographic process. Such an auxiliary structure may include aconductive electric trace or other passive electric device. In someimplementations, the auxiliary structure may include more than onelayer. For example, auxiliary structure may, in some implementations,include layers 1105, 1130, and 1135. As a result, interferometricstructure 1120, for example, may be considered an auxiliary structure.Where the auxiliary structure includes more than one layer, not alllayers of the auxiliary structure need also be used to coat alight-turning feature. More generally, one or more layers used to coat alight-turning feature may also be used to form the auxiliary structure,but it is understood that the auxiliary structure may include layers notincluded in the coated light-turning feature, and vice versa. Inimplementations where the auxiliary structure includes multiple layers,multiple layers of materials may be deposited on the light guide inorder to form auxiliary structure and to coat the recess of thelight-turning feature, and the deposited layer(s) may then be etched toform the auxiliary structure and coated light-turning feature. Invarious implementations, after etching the deposited material,additional layers may be deposited on the auxiliary structure that arenot then formed in the recesses of the light-turning features, and viceversa. Hence, more generally, the auxiliary structure is at leastpartially formed of the material coating at least some of the recesses.

As illustrated in the implementation of FIG. 11B, conductive line 1105is electrically connected to metalized light-turning feature 920.However, it is understood that such an electrical connection isoptional. Hence, in some implementations, not all of the metalizedlight-turning features are part of an electrode system capable ofsensing the proximity of a conductive body (touch-sensing electronics930). This is because the light-turning features may be very dense(i.e., a large number for light-turning features for a given area),while touch-sensing electrodes need not be as dense. For example,touch-sensing electrodes may be horizontally spaced about 1-10 mm, about3-7 mm, or about 5 mm apart. Indeed, in some implementations (as in FIG.9D), no metalized light-turning features may be electrically connectedto the touch-sensing electronics 930. As described above, a singlematerial deposition may be used to fabricate such a grid of electrodesas well as to conformally coat the recess of a light-turning feature.

As illustrated in FIG. 11B, the display 810 is not always immediatelyadjacent to the light guide 910. However, it is to be understood that insome implementations display 810 may be immediately adjacent to thelight guide 910 which includes the illumination device illuminatingdisplay 810. In other implementations, an air gap may be formed betweenthe light guide 910 and the display 810. Further, in otherimplementations, there may be one or more layers between light guide 910and display 810. In such implementations, the one or more layers may ormay not include an air gap.

As previously discussed in FIGS. 10A and 10B, some implementations of atouch sensor include a plurality of elongate electrodes elongated alongan x direction separated by a dielectric layer and stacked over aplurality of electrodes elongated in a y direction. It may beadvantageous in some implementations, however, to form the grid of X andY electrodes in a single plane or surface. In other words, the grid of Xand Y electrodes may be formed on the same surface. In suchimplementations, the electrodes elongated in one direction, e.g., the xdirection, are electrically isolated from the electrodes elongated inthe other direction, e.g., the y direction. FIGS. 12A-12B are examplesof illustrations of implementations of light guides with metalizedlight-turning features with integrated touch sensor showing X and Yelectrodes formed in a single plane or surface.

For example, in the implementation depicted in FIG. 12A, electrode 1010extends along the x direction and electrode 1020 extends along the ydirection. Electrode 1010 and electrode 1020 may be formed in a singleplane. In the illustrated implementation in FIG. 12A, electrodes 1010and electrodes 1020 are formed on the surface of a glass or otheroptically transparent substrate 1210. In some implementations, theelectrodes 1010, 1020 may be auxiliary structures formed in a mannersimilar to that of the conductive line 1105, as described aboveregarding FIG. 11B. Over the optical substrate 1210 is formed a turninglayer 1215. The optical substrate 1210 and turning layer 1215 togethermake up the light guide 910. While, for the purposes of ease ofillustration, turning layer 1215 is shown much thicker than substrate1210, in various implementations the substrate 1210 may be thicker thanthe relatively thin turning layer 1215. As illustrated in theimplementation of FIG. 12A, electrode 1020 is patterned so as to providefor a gap 1220 to allow electrode 1010 to traverse electrode 1020 in adirection perpendicular to the direction of electrode 1020 so as toisolate electrode 1010 and electrode 1020. While FIG. 12A illustrateselectrodes 1010 and 1020 as perpendicular from each other, they may benon-parallel but not necessarily perpendicular. The two sides ofelectrode 1020 are bridged over electrode 1010 through conductive bridge1230 by forming vias 1240 in the turning layer. The vias 1240 includefacets that may be angled appropriately to turn light guided in lightguide 910. The vias 1240 are shown formed on both sides of the gap 1220.As illustrated, vias 1240 are conical, but it is understood that theymay be formed in any shape that provides for a facet capable of turninglight out of light guide 910, such as pyramidal or other profile (like aline or line segment similar to light-turning features 901 a and 901 bin FIG. 9A). In one implementation, the vias 1240 may be metalized byconformal deposition of the conductive bridge 1230 in the vias 1240,which expose electrode 1020. However, vias 1240 may be separately filledwith conducting material, which may also be reflective. In oneimplementation, vias 1240 provide a facet that is a 45° angle withrespect to a plane parallel to the plane of substrate 1210.

Vias 1240 may also serve as a metalized light-turning feature 920 in theturning layer 1215. Turning layer 1215 may include metalized ornon-metalized light-turning features other than vias 1240. As depictedin FIG. 12A, a pair of metalized light-turning features 920 are formedon opposite sides of electrode 1010. Metalized light-turning features920 act as conductive vias 1240 connecting one side of electrode 1020with the other side of electrode 1020 along the y direction. Metalizedlight-turning features 920 may both reflect light towards a display toilluminate a display device while also acting as electrical vias 1240 tobridge electrode 1020. As such, the conductors formed in metalizedlight-turning features 920 perform both optical functions in anillumination device and electrical functions in a touch sensor toprovide for an “integrated” illumination device with touch sensorcapability 840. Hence, metalized light-turning features 920 may be inelectrical communication with a larger electrode system that is atouch-sensing electrode system capable of sensing a change to acapacitance of the conductor in the metalized light-turning features 920induced by the proximity of a human finger.

Electrodes 1010 and 1020 as well as bridge 1230 are conductive and mayinclude reflective metallic conductors or transparent conductors, suchas ITO. Preferably, electrodes 1010 and 1020 are transparent, whilebridge 1230 is reflective. In such an implementation, reflections ofambient light from bridge 1230 may be masked with an interferometricstructure similar to that of FIG. 11B. It is understood that the vias1240, electrodes 1010 and 1020 and bridge 1230 may not be drawn toscale. Electrodes 1010 and 1020 (and to a lesser degree bridge 1230) maybe patterned to have a small footprint so as to minimize any effect onlight propagating in the light guide 910. Hence, electrodes 1010 and1020 and bridge 1230 may, in some implementations, have a smaller widththan via 1240. The implementation of FIG. 12A may be formed bydepositing and patterning electrodes 1010 and 1020. Electrodes 1010 and1020 and gap 1220 may be formed by patterning a standard pre-coatedITO-coated glass substrate which is commercially and readily available.Gap 1220 may be approximately 50 μm across, but wider or narrowerdesigns may be employed, such as, for example gaps between about 10-1000μm, or about 20-500 μm. In such implementations, an ITO-coated glass maybe patterned to form electrodes 1010 in the x direction and electrodes1020 in the y direction patterned with gaps 1220 in one or the otherdirection to prevent the intersection of electrode lines. In such animplementation, the glass substrate can serve as the substrate of alight guide 910. Then turning layer 1215 may be deposited or depositedover substrate 1210. In some implementations, layer 1215 may be a SiONlayer that is index matched to substrate 1210. A taper etch process maythen be used to define light-turning features and vias 1240 in turninglayer 1215. Vias may be approximately 5 μm across. In someimplementations, wider or narrower vias may be employed, e.g., the viasmay measure about 2-50, or about 3-30 μm across. Then, a reflectiveconductor layer may be deposited and etched to provide conductor-filledvias 1240, which may also serve as a metalized light-turning feature920.

With reference to FIG. 12B, another implementation of an electrodesystem comprising electrodes 1010, 1020 in the X and y direction formedin a single plane is depicted. In some implementations, the electrodes1010, 1020 may be auxiliary structures formed in a manner similar tothat of the conductive line 1105, as described above regarding FIG. 11B.As in the implementation depicted in FIG. 12A, a light guide 910includes a glass substrate 1210 and a light-turning layer 1215. However,the electrodes 1010 and 1020 and the gap 1220 in the presentimplementation are formed over the light-turning layer 1215. In thisimplementation, the bridge 1230 is formed underneath the electrodes 1010and 1020 and over the substrate 1210. In certain implementations of FIG.12B, conductive bridge 1230 may be formed of a transparent conductorwhile electrodes 1010 and 1020 may be formed of reflective metal, andmay hence be masked by an interferometric structure as noted above. Itis understood that the vias 1240, electrodes 1010 and 1020 and bridge1230 may not be drawn to scale. In some implementations, bridge 1230(and to a lesser degree electrodes 1010 and 1020) may be patterned tohave a smaller width than the diameter of the vias 1240, so as to reducethe impact of the bridge 1230 on light reflected off the surface of thevia 1240. In implementations where bridge 1230 is wider than vias 1240,it may block light that is reflected off vias 1240 from propagatingdownwards to an underlying display. Vias 1240 may include metalizedlight-turning features and may be metalized by conformal deposition ofelectrode 1230 extending into the vias 1240. In some implementations,the vias may have dimensions on the order of microns, while theelectrode 1230 (as well as the conformal coating of the via 1240) mayhave a thickness on the order of one tenth of a micron. Conductivematerial may be deposited onto substrate 1210 and patterned to formconductive bridge 1230. In some implementations conductive material mayinclude a transparent conductor. Conductive bridge 1230 may be alsoformed by patterning a standard pre-coated ITO-coated glass substratewhich is commercially and readily available. Turning layer 1215,light-turning features in turning layer 1215, and vias 1240 may all thenbe formed, for example, as described above regarding FIG. 12A. In someimplementations, the dimensions for gap 1220 and vias 1240 in theimplementation of FIG. 12B may be similar to those noted above regardingFIG. 12A. In certain implementations, the conductive bridge 1230 of theimplementation of FIG. 12A and the electrodes 1010 and 1020 of theimplementation of FIG. 12B may be laminated. In one example of such amethod, bridge 1230 or electrodes 1010, 1020 may be formed on the bottomof a lamination layer (not shown in FIGS. 12A and 12B), and the layermay then be laminated over turning layer 1215 to connect bridge 1230 orelectrodes 1010, 1020 with conducting vias 1240.

FIGS. 13A and 13B show examples of system block diagrams illustrating adisplay device 40 that includes a plurality of interferometricmodulators. The display device 40 can be, for example, a cellular ormobile telephone. However, the same components of the display device 40or slight variations thereof are also illustrative of various types ofdisplay devices such as televisions, e-readers and portable mediaplayers.

The display device 40 includes a housing 41, a display 30, an antenna43, a speaker 45, an input device 48, and a microphone 46. The housing41 can be formed from any of a variety of manufacturing processes,including injection molding, and vacuum forming. In addition, thehousing 41 may be made from any of a variety of materials, including,but not limited to: plastic, metal, glass, rubber, and ceramic, or acombination thereof. The housing 41 can include removable portions (notshown) that may be interchanged with other removable portions ofdifferent color, or containing different logos, pictures, or symbols.

The display 30 may be any of a variety of displays, including abi-stable or analog display, as described herein. The display 30 alsocan be configured to include a flat-panel display, such as plasma, EL,OLED, STN LCD, or TFT LCD, or a non-flat-panel display, such as a CRT orother tube device. In addition, the display 30 can include aninterferometric modulator display, as described herein.

The components of the display device 40 are schematically illustrated inFIG. 13B. The display device 40 includes a housing 41 and can includeadditional components at least partially enclosed therein. For example,the display device 40 includes a network interface 27 that includes anantenna 43 which is coupled to a transceiver 47. The transceiver 47 isconnected to a processor 21, which is connected to conditioning hardware52. The conditioning hardware 52 may be configured to condition a signal(e.g., filter a signal). The conditioning hardware 52 is connected to aspeaker 45 and a microphone 46. The processor 21 is also connected to aninput device 48 and a driver controller 29. The driver controller 29 iscoupled to a frame buffer 28, and to an array driver 22, which in turnis coupled to a display array 30. A power supply 50 can provide power toall components as required by the particular display device 40 design.

The network interface 27 includes the antenna 43 and the transceiver 47so that the display device 40 can communicate with one or more devicesover a network. The network interface 27 also may have some processingcapabilities to relieve, e.g., data processing requirements of theprocessor 21. The antenna 43 can transmit and receive signals. In someimplementations, the antenna 43 transmits and receives RF signalsaccording to the IEEE 16.11 standard, including IEEE 16.11(a), (b), or(g), or the IEEE 802.11 standard, including IEEE 802.11a, b, g or n. Insome other implementations, the antenna 43 transmits and receives RFsignals according to the BLUETOOTH standard. In the case of a cellulartelephone, the antenna 43 is designed to receive code division multipleaccess (CDMA), frequency division multiple access (FDMA), time divisionmultiple access (TDMA), Global System for Mobile communications (GSM),GSM/General Packet Radio Service (GPRS), Enhanced Data GSM Environment(EDGE), Terrestrial Trunked Radio (TETRA), Wideband-CDMA (W-CDMA),Evolution Data Optimized (EV-DO), 1xEV-DO, EV-DO Rev A, EV-DO Rev B,High Speed Packet Access (HSPA), High Speed Downlink Packet Access(HSDPA), High Speed Uplink Packet Access (HSUPA), Evolved High SpeedPacket Access (HSPA+), Long Term Evolution (LTE), AMPS, or other knownsignals that are used to communicate within a wireless network, such asa system utilizing 3G or 4G technology. The transceiver 47 canpre-process the signals received from the antenna 43 so that they may bereceived by and further manipulated by the processor 21. The transceiver47 also can process signals received from the processor 21 so that theymay be transmitted from the display device 40 via the antenna 43.

In some implementations, the transceiver 47 can be replaced by areceiver. In addition, the network interface 27 can be replaced by animage source, which can store or generate image data to be sent to theprocessor 21. The processor 21 can control the overall operation of thedisplay device 40. The processor 21 receives data, such as compressedimage data from the network interface 27 or an image source, andprocesses the data into raw image data or into a format that is readilyprocessed into raw image data. The processor 21 can send the processeddata to the driver controller 29 or to the frame buffer 28 for storage.Raw data typically refers to the information that identifies the imagecharacteristics at each location within an image. For example, suchimage characteristics can include color, saturation, and gray-scalelevel.

The processor 21 can include a microcontroller, CPU, or logic unit tocontrol operation of the display device 40. The conditioning hardware 52may include amplifiers and filters for transmitting signals to thespeaker 45, and for receiving signals from the microphone 46. Theconditioning hardware 52 may be discrete components within the displaydevice 40, or may be incorporated within the processor 21 or othercomponents.

The driver controller 29 can take the raw image data generated by theprocessor 21 either directly from the processor 21 or from the framebuffer 28 and can re-format the raw image data appropriately for highspeed transmission to the array driver 22. In some implementations, thedriver controller 29 can re-format the raw image data into a data flowhaving a raster-like format, such that it has a time order suitable forscanning across the display array 30. Then the driver controller 29sends the formatted information to the array driver 22. Although adriver controller 29, such as an LCD controller, is often associatedwith the system processor 21 as a stand-alone Integrated Circuit (IC),such controllers may be implemented in many ways. For example,controllers may be embedded in the processor 21 as hardware, embedded inthe processor 21 as software, or fully integrated in hardware with thearray driver 22.

The array driver 22 can receive the formatted information from thedriver controller 29 and can re-format the video data into a parallelset of waveforms that are applied many times per second to the hundreds,and sometimes thousands (or more), of leads coming from the display'sx-y matrix of pixels.

In some implementations, the driver controller 29, the array driver 22,and the display array 30 are appropriate for any of the types ofdisplays described herein. For example, the driver controller 29 can bea conventional display controller or a bi-stable display controller(e.g., an IMOD controller). Additionally, the array driver 22 can be aconventional driver or a bi-stable display driver (e.g., an IMOD displaydriver). Moreover, the display array 30 can be a conventional displayarray or a bi-stable display array (e.g., a display including an arrayof IMODs). In some implementations, the driver controller 29 can beintegrated with the array driver 22. Such an implementation is common inhighly integrated systems such as cellular phones, watches and othersmall-area displays.

In some implementations, the input device 48 can be configured to allow,e.g., a user to control the operation of the display device 40. Theinput device 48 can include a keypad, such as a QWERTY keyboard or atelephone keypad, a button, a switch, a rocker, a touch-sensitivescreen, or a pressure- or heat-sensitive membrane. The microphone 46 canbe configured as an input device for the display device 40. In someimplementations, voice commands through the microphone 46 can be usedfor controlling operations of the display device 40.

The power supply 50 can include a variety of energy storage devices asare well known in the art. For example, the power supply 50 can be arechargeable battery, such as a nickel-cadmium battery or a lithium-ionbattery. The power supply 50 also can be a renewable energy source, acapacitor, or a solar cell, including a plastic solar cell or solar-cellpaint. The power supply 50 also can be configured to receive power froma wall outlet.

In some implementations, control programmability resides in the drivercontroller 29 which can be located in several places in the electronicdisplay system. In some other implementations, control programmabilityresides in the array driver 22. The above-described optimization may beimplemented in any number of hardware and/or software components and invarious configurations.

The various illustrative logics, logical blocks, modules, circuits andalgorithm steps described in connection with the implementationsdisclosed herein may be implemented as electronic hardware, computersoftware, or combinations of both. The interchangeability of hardwareand software has been described generally, in terms of functionality,and illustrated in the various illustrative components, blocks, modules,circuits and steps described above. Whether such functionality isimplemented in hardware or software depends upon the particularapplication and design constraints imposed on the overall system.

The hardware and data processing apparatus used to implement the variousillustrative logics, logical blocks, modules and circuits described inconnection with the aspects disclosed herein may be implemented orperformed with a general purpose single- or multi-chip processor, adigital signal processor (DSP), an application specific integratedcircuit (ASIC), a field programmable gate array (FPGA) or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described herein. A general purpose processor may be amicroprocessor, or, any conventional processor, controller,microcontroller, or state machine. A processor may also be implementedas a combination of computing devices, e.g., a combination of a DSP anda microprocessor, a plurality of microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suchconfiguration. In some implementations, particular steps and methods maybe performed by circuitry that is specific to a given function.

In one or more aspects, the functions described may be implemented inhardware, digital electronic circuitry, computer software, firmware,including the structures disclosed in this specification and theirstructural equivalents thereof, or in any combination thereof.Implementations of the subject matter described in this specificationalso can be implemented as one or more computer programs, i.e., one ormore modules of computer program instructions, encoded on a computerstorage media for execution by, or to control the operation of, dataprocessing apparatus.

Various modifications to the implementations described in thisdisclosure may be readily apparent to those skilled in the art, and thegeneric principles defined herein may be applied to otherimplementations without departing from the spirit or scope of thisdisclosure. Thus, the disclosure is not intended to be limited to theimplementations shown herein, but is to be accorded the widest scopeconsistent with the claims, the principles and the novel featuresdisclosed herein. The word “exemplary” is used exclusively herein tomean “serving as an example, instance, or illustration.” Anyimplementation described herein as “exemplary” is not necessarily to beconstrued as preferred or advantageous over other implementations.Additionally, a person having ordinary skill in the art will readilyappreciate, the terms “upper” and “lower” are sometimes used for ease ofdescribing the figures, and indicate relative positions corresponding tothe orientation of the figure on a properly oriented page, and may notreflect the proper orientation of the IMOD as implemented.

Certain features that are described in this specification in the contextof separate implementations also can be implemented in combination in asingle implementation. Conversely, various features that are describedin the context of a single implementation also can be implemented inmultiple implementations separately or in any suitable subcombination.Moreover, although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various systemcomponents in the implementations described above should not beunderstood as requiring such separation in all implementations, and itshould be understood that the described program components and systemscan generally be integrated together in a single software product orpackaged into multiple software products. Additionally, otherimplementations are within the scope of the following claims. In somecases, the actions recited in the claims can be performed in a differentorder and still achieve desirable results.

What is claimed is:
 1. An illumination device comprising: a light guideincluding light-turning features, wherein the light-turning featuresinclude recesses formed on the light guide and extending down into thelight guide; a material coating at least some of the recesses; and anauxiliary structure formed outside of the recesses and on the lightguide, the auxiliary structure at least partially formed of the materialcoating at least some of the recesses, and spaced apart from thematerial coating the at least some of the recesses, wherein the lightguide has a top surface, wherein the light-turning features are formedon the top surface of the light guide, and wherein the auxiliarystructure contacts the top surface of the light guide.
 2. Theillumination device of claim 1, wherein the material includes a metal.3. The illumination device of claim 2, wherein the auxiliary structureis an electrode.
 4. The illumination device of claim 3, wherein theelectrode is electrically connected to an electronic system.
 5. Theillumination device of claim 4, wherein the electronic system is a touchsensor system capable of sensing the proximity of a conductive body andthe electrode is part of the touch sensor system.
 6. The illuminationdevice of claim 5, wherein the touch sensor system includes theelectrode extending in one direction and another electrode extending inanother, non-parallel direction; the electrode has a gap with two sidesformed to prevent the intersection of the electrode and the otherelectrode, the gap breaking the electrode into a first side and a secondside; and the electrode and the other electrode are formed on a singlesurface.
 7. The illumination device of claim 5, wherein thetouch-sensing electrode system includes the electrode extending in onedirection and another electrode extending in another, non-paralleldirection; the electrode has a gap with two sides formed to prevent theintersection of the electrode and the other electrode, the gap breakingthe electrode into a first side and a second side; and the electrode andthe other electrode are formed on a single surface.
 8. The illuminationdevice of claim 7, wherein the first side of the electrode iselectrically connected to the second side of the electrode across thegap through a conductive bridge on a level different from a level of theelectrode and the other electrode, wherein vertically extending contactstructures electrically connect the bridge to the first and second sidesof the electrode.
 9. The illumination device of claim 7, wherein theconductive bridge includes a reflective conductor.
 10. The illuminationdevice of claim 7, wherein the contact structures include a reflectiveconductor.
 11. The illumination device of claim 8, wherein the contactstructures comprise a reflective conductor.
 12. The illumination deviceof claim 6, wherein the electronic system is capable of sensing theproximity of a human finger.
 13. The illumination device of claim 3,wherein the auxiliary structure forms a passive electric device.
 14. Theillumination device of claim 3, wherein the auxiliary structure forms anactive electric device.
 15. The illumination device of claim 1, whereinthe material coating at least some of the recesses is part of aplurality of layers of different materials extending into the at leastsome of the recesses.
 16. The illumination device of claim 15, whereinthe plurality of layers form an interferometric structure.
 17. Theillumination device of claim 16, wherein the auxiliary structureincludes an interferometric stack formed of a stack of materialscorresponding to the plurality of layers forming the interferometricstructure in the at least some of the recesses.
 18. The illuminationdevice of claim 17, wherein the interferometric stack is configured tobe more reflective of light striking a bottom surface of theinterferometric stack than light striking a top surface of theinterferometric stack
 19. The illumination device of claim 1, whereinthe auxiliary structure is spaced apart from the light-turning features.20. The illumination device of claim 1, wherein the light guide isdisposed over a reflective display.
 21. The illumination device of claim20, wherein the reflective display includes display elements includinginterferometric modulators.
 22. The illumination device of claim 1,further comprising: a display which can be illuminated by the lightguide; a processor that is configured to communicate with the display,the processor being configured to process image data; and a memorydevice that is configured to communicate with the processor.
 23. Theillumination device as recited in claim 22, further comprising a drivercircuit configured to send at least one signal to the display.
 24. Theillumination device as recited in claim 23, further comprising acontroller configured to send at least a portion of the image data tothe driver circuit.
 25. The illumination device as recited in claim 22,further comprising an image source module configured to send the imagedata to the processor.
 26. The illumination device as recited in claim25, wherein the image source module includes at least one of a receiver,transceiver, or transmitter.
 27. The illumination device as recited inclaim 22, further comprising: an input device configured to receiveinput data and to communicate the input data to the processor.
 28. Amethod of manufacturing an integrated illumination device, the methodcomprising: depositing a material on a light guide includinglight-turning features, the light- turning features including recessesformed on the light guide and extending down into the light guide; andetching the deposited material to form an auxiliary structure andsimultaneously leaving some of the material in at least some of therecesses formed on the light guide, wherein the light guide has a topsurface, wherein the light-turning features are formed on the topsurface of the light guide, and the material is deposited on the topsurface of the light guide, and wherein the auxiliary structure contactsthe top surface of the light guide and is spaced apart from the materialcoating the at least some of the recesses formed on the light guide. 29.The method of claim 28, wherein the material includes a metal.
 30. Themethod of claim 29, wherein etching the material to form the auxiliarystructure includes etching the material to form an elongate electrode.31. The method of claim 30, further comprising connecting the electrodeto a touch-sensing electrode system capable of sensing the proximity ofa conductive body.
 32. The method of claim 31, wherein the electrodesystem is capable of sensing the proximity of a human finger.
 33. Themethod of claim 28, wherein the auxiliary structure includes aconductive electric trace extending across an entire viewable surface ofa display.
 34. An illumination device comprising: a guiding means forguiding light including turning means for turning light out of theguiding means; a coating means for coating at least some of the turningmeans to render the turning means reflective; and a conductive means forconducting electricity, the conductive means formed outside of theturning means, contacting the guiding means, spaced apart from thecoating means, and formed of the same material as the coating means. 35.The illumination device of claim 34, wherein: the guiding means includesa light guide; the turning means includes a light-turning facet; thecoating means includes a reflective material; or the conductive meansincludes a conductive material.
 36. The illumination device of claim 34,wherein the coating means and the conductive means include ananti-reflection means.
 37. The illumination device of claim 36, whereinthe anti-reflection means includes a stack of layers of differentmaterials.
 38. The illumination device of claim 37, wherein the layersof different materials form an interferometric stack.
 39. Theillumination device of claim 34, wherein the coating means and theconductive means each include a metal.